Turboprop engine with compressor turbine shroud

Patent metadata

Field	Value
Publication number	US-9410441-B2
Application number	US-201213613904-A
Country	US
Kind code	B2
Filing date	Sep 13, 2012
Priority date	Sep 13, 2012
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

A turboprop engine including an annular outer case including a mount ring for attachment to an aircraft along a plane to transfer loads from a propeller and having an annular flange extending radially inwardly therefrom within the plane, an annular turbine support case received within the outer case and connected to the outer case only through a direct connection with the annular flange allowing a limited relative pivoting motion between the turbine support case and the mount ring, and a turbine section including a rotor closely surrounded by a shroud with an annular tip clearance being defined therebetween, the shroud being directly connected to and located by the turbine support case. A method of isolating a turbine shroud from propeller loads in a propeller engine is also disclosed.

First claim

The invention claimed is:

1. A turboprop engine comprising:
an outer case including a mount ring, the mount ring defining a mount plane and an attachment location for attachment to an aircraft within the mount plane, the outer case being annular, the mount ring configured for attachment to the aircraft at the attachment location to transfer loads from a propeller, the mount ring having a flange extending radially inwardly therefrom within the mount plane, the flange being annular;
a turbine support case received within the outer case and being annular, the turbine support case being connected to the outer case only through a direct connection with the flange of the mount ring, the direct connection defining a pivot point, the turbine support case and the mount ring being relatively movable around the pivot point allowing a limited relative pivoting motion; and
a turbine section including a rotor closely surrounded by a shroud with an annular tip clearance being defined therebetween, the shroud being directly connected to and located by the turbine support case.

2. The engine as defined in claim 1 , wherein the mount ring is a single plane mount.

3. The engine as defined in claim 1 , wherein the turbine section further includes at least one stator supported along an outer perimeter thereof by the turbine support case.

4. The engine as defined in claim 1 , wherein the turbine support case includes an annular outer section extending downstream and radially inwardly from the flange of the mount ring and an annular inner section extending upstream and radially inwardly from a downstream end of the annular outer section, an upstream end of the inner section being directly connected to the shroud.

5. The engine as defined in claim 1 , wherein the turbine support case includes a radially outwardly extending flange connected to the flange of the mount ring, the turbine support case including an end wall extending axially beyond the flange of the turbine support case toward the flange of the mount ring and abutting an adjacent portion of the outer case, the flange of the mount ring and the flange of the turbine support case being interconnected by a circumferential array of fasteners extending through the flange of the mount ring and the flange of the turbine support case, and a spring member being compressed between the turbine support case and the adjacent portion of the outer case, the spring member being located radially inwardly of the circumferential array of fasteners.

6. The engine as defined in claim 5 , wherein the outer case includes a downstream portion extending downstream from the mount ring radially outwardly of the flange of the mount ring and around the turbine support case, and the adjacent portion of the outer case is an upstream portion extending upstream from the flange of the mount ring, the spring member being compressed between the turbine support case and the upstream portion.

7. The engine as defined in claim 6 , wherein the upstream portion includes a radially outwardly extending flange received between the flange of the mount ring and the flange of the turbine support case and connected to the flange of the mount ring by the circumferential array of fasteners, the end wall of the turbine support case abutting the flange of the upstream portion.

8. The engine as defined in claim 7 , wherein the upstream portion includes an end wall extending axially beyond the flange thereof of the upstream portion and surrounded by the end wall of the turbine support case, the spring member being received between the end wall of the upstream portion and an adjacent shoulder of the turbine support case.

9. A turboprop engine comprising:
an outer case including a mount ring, the mount ring defining a mount plane and an attachment location for attachment to an aircraft within the mount plane, the mount ring configured for attachment to the aircraft at the attachment location, the outer case being annular, the mount ring having a flange extending radially inwardly therefrom within the mount plane, the flange being annular, the outer case including a portion extending from the mount ring to a bearing housing supporting of a shaft of the engine and defining a load path through the portion extending from the mount ring to the bearing housing;
a turbine support case received within the outer case and connected to the outer case only through a direct connection with the flange of the mount ring, the turbine support case being annular, the direct connection defining a pivot point allowing a limited relative pivoting motion between the turbine support case and the mount ring, the turbine support case extending free of the load path;
a turbine section received within the outer case and including a rotor in driving engagement with the shaft and closely surrounded by a shroud with an annular tip clearance being defined between the rotor and the shroud, the shroud being directly connected to and located by the turbine support case.

10. The engine as defined in claim 9 , wherein the mount ring is a single plane mount.

11. The engine as defined in claim 9 , wherein the turbine section includes at least one stator supported around an outer perimeter thereof by the turbine support case.

12. The engine as defined in claim 11 , wherein the turbine support case includes an annular outer section extending downstream and radially inwardly from the flange of the mount ring and an annular inner section extending upstream and radially inwardly from a downstream end of the annular outer section, the annular inner section supporting the at least one stator of the turbine section, an upstream end of the annular inner section being directly connected to the shroud.

13. The engine as defined in claim 9 , wherein the turbine support case includes a radially outwardly extending flange connected to the flange of the mount ring, the turbine support case including an end wall extending axially beyond the flange of the turbine support case toward the flange of the mount ring and abutting an adjacent portion of the outer case, the flange of the mount ring and the flange of the turbine support case being interconnected by a circumferential array of fasteners extending through the flange of the mount ring and the flange of the turbine support case, and a spring member being compressed between the turbine support case and the adjacent portion of the outer case, the spring member being located radially inwardly of the circumferential array of fasteners.

14. The engine as defined in claim 13 , wherein the adjacent portion of the outer case is an upstream portion extending upstream from the flange of the mount ring, the spring member being compressed between the turbine support case and the upstream portion, the outer case further comprising a downstream portion extending downstream from the mount ring radially outwardly of the flange of the mount ring and around the turbine support case.

15. The engine as defined in claim 14 , wherein the upstream portion includes a radially outwardly extending flange received between the flange of the mount ring and the flange of the turbine support case and connected to the flange of the mount ring by the circumferential array of fasteners, the end wall of the turbine support case abutting the flange of the upstream portion.

16. A method of assembling the turboprop engine according to claim 9 such that the shroud is isolated from propeller loads, the method comprising:
supporting the shaft of the engine with the portion of the outer case extending from the mount ring to the bearing housing and defining the load path f

Assignees

• Macfarlane Ian Alexander
• Pratt & Whitney Canada

Inventors

• Macfarlane Ian Alexander

Classifications

• F02C6/206

  the vehicles being airscrew driven · CPC title

• F05D2230/642

  using maintaining alignment while permitting differential dilatation · CPC title

• F05D2250/411

  in rotation · CPC title

• Y10T29/49236

  Fluid pump or compressor making · CPC title

• F01D25/246 Primary

  Fastening of diaphragms or stator-rings · CPC title